Some uncommon Penn Dixie fossils

With thousands of visitors to Penn Dixie each year, really cool fossils are uncovered fairly often. With a trained eye and determined spirit, our visitors never cease to amaze the staff and volunteers with what they discover.

Dr. Edgar Kooijman, Director of the Biotechnology Program at Kent State University sent us these photos and descriptions of some uncommon fossils from a trip to the site a couple of years ago. His specimens — a trilobite, a snail, a crinoid, and an amminoid — showcase the diversity of marine life that existed in our region during the Late Devonian Period.

The head of a Bellacartwrightia trilobite.

From Dr. Kooijman:

This rolled trilobite was identified as a Bellacartwrightia calliteles and was found during the field trip of the North Coast Fossil Club in May 2013. It came from the main trilobite layer [in the Windom Shale], and was prepped by Brian Dasno from Watertown NY. This was no small task as the specimen was essentially split in two. The eyes and some of the carapace were on one side, and the rest on another. While the specimen was crushed during or after fossilization it is complete and all the spines are visible. The “spikes” coming from the front of the head are the tail spines. The dorsal spines are also beautifully visible.

The following three specimens were all found during the May 2014 field trip of the North Coast Fossil Club, from Cleveland OH. They were prepped by Marc Behrendt.

An Arthroacantha crinoid holdfast.

From Dr. Kooijman:

The crinoid cup is from a species that is commonly found in the Sylica shale of Ohio, but which is rare (at least complete cups are) in the Windom shale at Penn Dixie. The name of this species is Arthroacantha carpenteri (Hinde). The “nob” at the top is where the stem would have been attached. Stem fragments are common fossils in the shale of Penn Dixie. Also note the numerous scars of the side of the crinoid cup. These scars used to hold spines that may have served to ward of snails that loved to feed on crinoids. The spines are not preserved in this specimen but the attachment points are easily visible.

A gastropod (snail) — potentially Bucculentium.

From Dr. Kooijman:

The snail is from the genus Platyceras, and the species may be Bucculentum. And was identified from among the different species found in the Sylica shale of north west Ohio. It was found just above the main trilobite layer at the edge of the digging pit during the 2014 season. It is the largest snail I have ever found at Penn Dixie.

A cast of an ammonoid — predatory cephalopod

From Dr. Kooijman:

The ammonite was found in the main trilobite layer. Note that the original shell material is not preserved and only the cast of this mollusk is visible. No genus name for this specimen is known. These aminoids are occasionally found in the Windom shale.